Add zip code to the list of things that impact how old your skin looks: A recent study ranked 50 U.S. cities to determine where residents are the most at risk for skin damage and premature aging by 2040 (sounds far away, but that's only 24 years from now). The results? Philadelphia, Denver, Seattle, Chicago, and Minneapolis took the top five spots (i.e. were the most wrinkle-prone), while San Francisco, Virginia Beach, Jacksonville, West Palm Beach, and San Jose were the least.

The meta-analysis, conducted by RoC Skincare and research firm Sterling's Best Places, assessed a variety of lifestyle and environmental factors—things like stress levels, commute time, and weather. So, if you're not going to pick up and move, how can you combat these skin saboteurs? Joshua Zeichner, M.D., assistant clinical professor of dermatology at Mount Sinai Hospital in New York City, helped us break it down.

Culprit #1: Stress

It wreaks havoc on your mind, body, and skin: "Stress is associated with increased inflammation," explains Dr. Zeichner. "It increases cortisol, which in turn interferes with your skin's ability to heal itself and combat this inflammation." Not to mention that when skin is in a stressed state it can't defend itself against other environmental stressors, such as pollution (more on that next). And aging issues aside, stress also increases the amount of oil in your skin, upping the likelihood of breakouts.

The Fix: Unfortunately, there's no topical way to treat stressed skin, so take this as added incentive to make a conscious effort to relax as much as humanely possible. Consider this your excuse to go ahead and take that mental health day! And of course, exercise—whether in the form of an intense HIIT workout or a chill yoga flow—can perform wonders on your stress levels.

Culprit #2: Pollution

This includes both smog and particulate matter, a.k.a. tiny bits of grime that sit on and penetrate into skin, explains Dr. Zeichner. Both lead to free radical damage, a major cause of aged skin, irritation, and inflammation. (Check out even more reasons why the air you breathe might be your skin's biggest enemy.)

The Fix: It may sound simple, but thoroughly washing your face is an easy way to remove excess particulate matter. Dr. Zeichner suggests using a cleansing brush, like the Clarisonic Mia Fit ($219; clarisonic.com), to get your complexion completely clean. You can also incorporate a purifying mask into your weekly routine to help de-gunk your pores. Our pick: Tata Harper Purifying Mask ($65; tataharperskincare.com). Antioxidant-rich products are also a must, since they're effective at combating all those free radicals. Try Elizabeth Arden Prevage City Smart Broad Spectrum SPF 50 Hydrating Shield ($68; elizabetharden.com), which contains green tea and ferulic acid.

Culprit #3: Smoking

No surprise here, the nasty habit constricts blood vessels, decreasing the flow of oxygen and vital nutrients to your skin.

The Fix: Stop. Smoking. (Insert obligatory 'duh' here.)

Culprit #4: Heat

Heat is actually another form of radiation known as infrared radiation, yet another source of those no-good-for-your-skin free radicals. It also dilates blood vessels and may promote inflammation, notes Dr. Zeichner.

The Fix: Since you're already using sunscreen daily (right??), look for one that not only safeguards your skin from UVA and UVB rays, but also infrared radiation, like SkinMedica Total Defense + Repair Broad Spectrum Sunscreen SPF 34 ($68; skinmedica.com).

Culprit #5: Commuting

Lengthy schleps to and from work are no fun, but they can also contribute to wrinkles for a few different reasons, says Dr. Zeichner. "The sun's UVA rays penetrate through the glass of your car, train, or bus window, damaging your skin," he explains. Plus, longer commute times often mean less time spent working out, and there's a lot of data showing that exercise leads to healthier skin, he notes.

The Fix: Since shortening your commute likely isn't an option, be sure to slather on a broad-spectrum sunscreen before you leave the house (every single morning!), and be extra cognizant about making sure to clear enough time in your schedule for a daily workout.

Regardless of which factor is the biggest issue in your city, diligently using a moisturizer both A.M. and P.M. is universally beneficial; it helps maintain a healthy skin barrier, keeping hydration in, and irritants out. A retinol-based night treatment is also a good choice, no matter where you live. The gold-standard anti-ager boosts cell turnover and stimulates collagen production for a smoother, younger-looking complexion.